1. Field Of The Invention
The present invention relates to dunnage air bags, and more particularly pertains to an improved dunnage air bag of the type employed in the packaging and shipping of various articles and materials for the purpose of filling void air space to prevent shifting of the load and damage to goods.
2. Description Of The Prior Art
U.S. Pat. No. 3,028,981, which issued to B. Ford et al. on Apr. 10, 1962, discloses a dunnage air bag which utilizes a polyethylene film to form a balloon with an expansion bellows disposed between semi-rigid corrugated boards. U.S. Pat. No. 3,072,270, which issued to T. Tolby on Jan. 8, 1963, discloses a similar inflatable cargo cushion which employs a separable inflatable bladder formed by polyethylene film, which is disposed within a paper or cardboard bag. U.S. Pat. No. 3,506,143, which issued to C. Evans on Apr. 14, 1970, discloses an inflatable dunnage bag possessing an air bladder enclosed in a multi-ply container. U.S. Pat. No. 4,591,519, which issued to H. Liebel on May 27, 1986, discloses an inflatable cargo bag possessing two overlying relatively stiff paperboard sheets disposed on opposite sides of a separate plastic air bladder, such that the bag is substantially self-supporting in an un-inflated condition. Peripheral edge flaps on one larger sheet are folded over and glued to the other sheet.
These prior art inflatable dunnage bags suffer from several disadvantages. The separate manufacture and insertion of the air bladder is relatively expensive. Also, during insertion, the bladder can be nicked, cut, torn, or abraded, resulting in failure of the bag upon attempted inflation. Prior art bags which utilize a bladder inserted into a paper tube require expensive machines to form the paper tubes. Nonrigid type prior art dunnage bags collapse when un-inflated, making them difficult for one person to position and hold during inflation. The use of non-integral air bladders also creates the potential for the air bladder to sag, fold and crease within the outer container, leading to ultimate failure of the bag.